And nobody can guarantee the price of bitcoin at all time and that is why it is good for the long term investment. And whenever the price dip then it is to refill the wallet for whatever I have. If someone bought it when it is high and the price suddenly came down to the dip, he should not panic and all what he should do is to pick courage and keep hodling and one day the price would go up again.
No one is suggesting that you will never sell your holding. You will eventually sell it at some point but barely selling because of the market condition mean you weren't ready for long term investment in the first place.
An example might be helpful here, and there could be a couple of ways that decisions to diversify could take place and they do not necessarily involve selling BTC - though situations in which someone over allocates to bitcoin might result in some selling that might also be motivated to diversify... so it is not easy to overly generalize the circumstances in which a bitcoin investor might start to conclude that he has enough BTC or more than enough BTC.
Frequently, it seems that newbies will be talking about diversification in the beginning of their investment rather than later down the road, and so surely the way that an investment evolves may also affect how diversification decisions are made, and again there might not be any need to sell BTC during those kinds of situations, even though surely Troytech seems to be talking about selling BTC in a kind of context in which the BTC price goes up so then profits are taken and put into other assets, and those are not necessarily wrong ideas, even though it surely could be the case that there is a bit of a trading mentality going on that might still ultimately result in too many BTC being sold too soon and then getting put into either inferior investments or into consumption items that are couched as investments.. which is also not even necessarily a bad thing to get some pleasure out of the wealth that we accumulate as long as we aren't deceiving ourselves into some kind of erroneous beliefs regarding the trade-offs that we might end up making.
It is true that there are likely a lot of newbie investors who might not realize that bitcoin allows them to invest with quite small amounts and to build up their investment over time, and so sometimes poor people will either fail to invest or they will over invest in part motivated by incorrect ideas that they need a lot of capital to get started and/or to maintain their investment.
So when they actually put investing into bitcoin into practice, even in fairly modest ways, they may well come to realize that they do not need as much capital in the beginning as they had previously believed to have had been necessary and yeah, maybe even after a whole cycle, they have still ONLY built a relatively modest bitcoin investment and they are still in their early BTC accumulation stages, they still might start to come to appreciate that bitcoin investing (and any investing) tends to take a lot of time, and they end up being in a much better place after 4 years of investing as compared with if they had not invested into bitcoin... so they are both reinforced in the idea and personally learn through experience in regards to the better practices (including that they also may have personally learned from some of their application mistakes in their first whole cycle of investing into bitcoin).
So surely sticking through a whole cycle and being able to make it through a whole cycle should well be a learning experience, even if several mistakes are made along the way, too.
As _BlackStar, there may well be some members who are barely making ends meet, so they might have some weeks where their disposable income is not enough to buy BTC, and they also might end u selling some of their BTC when they should be buying, holding and/or using their back up funds or their emergency funds to take care of their expenses prior to spending from their bitcoin holdings... and yeah, there can be a lot of struggles for some newbies (especially poor ones) to both invest into bitcoin and also to maintain emergency funds, so these can be difficult areas to balance and to either not mistakes or to learn from mistakes when they are made.